Fermi surface topology and negative longitudinal magnetoresistance observed in centrosymmetric NbAs2 semimetal

TL;DR

This study investigates the magneto-transport properties of NbAs2, revealing large magnetoresistance, quantum oscillations, Fermi surface features, and potential topological states, contributing to understanding semimetal electronic structures.

Contribution

It provides detailed experimental and theoretical analysis of NbAs2's Fermi surface topology and magnetoresistance, highlighting potential topological phenomena.

Findings

Large non-saturating magnetoresistance up to 8000 at 9 T

Identification of four Fermi pockets via calculations and SdH oscillations

Observation of negative longitudinal magnetoresistance possibly linked to topological states

Abstract

We report transverse and longitudinal magneto-transport properties of NbAs2 single crystals. Attributing to the electron-hole compensation, non-saturating large transverse magnetoresistance reaches up to 8000 at 9 T at 1.8 K with mobility around 1 to 2 m^2V^-1S^-1. We present a thorough study of angular-dependent Shubnikov-de Haas (SdH) quantum oscillations of NbAs2. Three distinct oscillation frequencies are identified. First-principles calculations reveal four types of Fermi pockets: electron alpha pocket, hole beta pocket, hole gamma pocket and small electron delta pocket. Although the angular dependence of alpha, beta and delta agree well with the SdH data, it is unclear why the gamma pocket is missing in SdH. Negative longitudinal magnetoresistance is observed which may be linked to novel topological states in this material, although systematic study is necessary to ascertain its origin.